Fairly minor bug, but the username autocomplete doesn't rebuild its list of users immediately after hidden comments are loaded from the server, allowing for situations like the following where late-comers to the comment thread are excluded:

Causing the textarea to refocus fixes things, since it has the full list of comments to work with at that point. However, since the textarea is auto-focused after you click the link to load additional comments, it's not too hard to end up in a situation where you don't have all of the expected names displayed.

Ideally, the autocomplete list would be forced to update once the comments were done loading.